Pointing stick in a computer keyboard for cursor control

ABSTRACT

Apparatus for use in a computer keyboard for cursor control is disclosed. The apparatus includes a compound key which serves for both typing a character and for pointing operations, i.e. for cursor control like a mouse. For pointing operations, a pointing stick or shaft is pressed in a desired direction by a user for moving a cursor in a corresponding direction on a display screen. The pointing stick is disposed in an aperture that extends through a modified key cap, so that no additional keyboard space is required for the pointing device, thereby obviating a separate mouse, keyboard mounted trackball or the like. In an alternative embodiment, the pointing stick extends through an aperture in the keyboard space bar. In another embodiment, adjacent key caps are modified so as to fit closely around the key cap that houses the pointing stick without interfering with operation of either the pointing stick or the keyswiches.

This application is a continuation-in-part of commonly-assigned, U.S.application Ser. No. 08/104,777, filed Aug. 16, 1993, entitled MINIATUREISOMETRIC JOYSTICK which is a continuation-in-part of commonly-assigned,U.S. application Ser. No. 08/096,485, filed Jul. 22, 1993, nowabandoned, entitled KEYBOARD INTEGRATED POINTING DEVICE which is adivision of U.S. application Ser. No. 07/557,546, filed Jul. 24, 1990,now U.S. Pat. No. 5,231,386, entitled KEYSWITCH INTEGRATED POINTINGASSEMBLY; a continuation-in part of commonly-assigned, U.S. applicationSer. No. 29/011,676, filed Aug. 9, 1993, entitled COMPOUND KEY FORTYPING AND POINTING OPERATIONS IN A COMPUTER KEYBOARD; and acontinuation-in-part of commonly-assigned, U.S. application Ser. No.29/018,842, filed Feb. 16, 1994 entitled POINTING STICK AND KEYCAPENSEMBLE FOR USE IN A COMPUTER KEYBOARD, all incorporated herein by thisreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to apparatus for controllingcursor movement on a video display terminal (VDT) and more particularlyto a pointing stick apparatus which is integrated together withkeyswitches on a computer keyboard so as to minimize the size of thekeyboard.

2. Description of the Related Art

Prior art keyboard pointing devices for controlling a cursor on a VDTare known. For example, U.S. Pat. No. 4,680,577 to Straayer, et al. (the'577 patent) discloses a multi-purpose key on a computer keyboard forcontrolling the cursor. Strain gauges are coupled to the multi-purposekey, which also serves as a regular typing key, for sensing lateralforces applied by the user's fingertip for cursor control. One of theproblems with prior art devices, even those that are force-sensitive, isthat a user gets no response to lateral displacement initially, until anelectrode makes initial contact, for example, with an elastomericresistive layer. The initial contact causes a step response, asresistance drops from infinity to a measurable value--a jump the usermay not have anticipated or desired. Then, as force is increased,resistance falls rapidly, over some range, and finally falls more slowlywith the application of additional force. All of this is disconcertingto a user for most applications. U.S. Pat. No. 5,231,386 (the '386patent) discloses a keyswitch-integrated pointing device in which theforce sensors are "preloaded" to an operating state such that there isno "jump" when a user starts to point to move the cursor. Internationalpatent application PCT/US90/06831 owned by Lexmark International alsoshows pointing apparatus for use in a keyboard for cursor control.

Most prior art "joysticks" are not sensitive to vertical or "Z-axis"force, because they have a rigid pivot or support underlying thejoystick handle. As a result, vertical force cannot be measured ordetected. The '386 patent shows how to produce a signal proportional tovertical force. Such a signal can be used, for example, to control linewidth while drawing as a function of z-axis force on the pointingdevice.

One problem with the prior apparatus is that the multi-purpose keyswitchor integrated keyswitch combines typing and cursor control into the samekeycap. Some users, however, prefer to have a separate, differentcontrol or button for cursor control. A separate button is advantageousbecause the computer can detect actuation of the cursor control asdistinguished from typing. The prior art '577 patent, for example,required a separate switch to enable the pointing sensors, since theywere built into the typing key. A separate "pointing stick" has thisadvantage and does not require another switch; it can remain always"on". However, a separate pointing stick takes up precious keyboardspace. For example, some portable or laptop computers have a trackballbelow the spacebar or off the side of the keyboard. These are notconvenient. The need remains therefore to provide a pointing stick forcursor control without taking any space on the keyboard.

SUMMARY OF THE INVENTION

The present invention comprises a pointing stick built into a keyboardtogether with one or more regular typing keys. This combination iscalled a "compound key". In a first embodiment, a "compound key" has apointing stick that extends upward through one side wall of the key cap.

According to a second embodiment, the compound key includes a pointingstick that extends through a corner of the key cap.

According to a third embodiment, the compound key includes a key caphaving a rounded extension on a corner of the key cap, the roundedextension having a central aperture, and a pointing stick extendsthrough the aperture.

According to a fourth embodiment, the compound key includes a pointingstick that protrudes though a hole in the space bar of a computerkeyboard.

According to a fifth embodiment of the invention, a keycap ensemblecomprises a set of three modified keycaps, together with a pointingstick extending through one of the modified key caps. Each of the first,second and third key caps is coupled to a respective underlyingkeyswitch for typing a corresponding alphanumeric character. Forexample, the first, second and third key caps may be arranged adjacenteach other in a generally triangular configuration for fitting withinthe usual typing array of key caps in a computer keyboard. The first keycap has a rounded extension forerod along a selected face thereof, andthe extension has a central aperture formed therein for receiving a"pointing stick" shaft. The shaft is sized and arranged so as to extendthrough the aperture to a predetermined height slightly above a topsurface of the first key cap for actuation by a user's fingertip. Theaperture is sized so as to allow slight lateral motion of the shaft forcursor control.

The apparatus is designed to fit within a keyboard typing array withoutaltering its dimensions. Toward that end, at least one of the second andthird key caps had a modified region so as to form a generally concavegap between the said one key cap and the rounded extension of the firstkey, whereby the said rounded extension does not interfere with normaloperation of the adjacent key cap. In a preferred embodiment, therounded extension is formed along a rear face of the first key cap; andeach of the second and third key caps includes a respective modifiedportion so as to form a corresponding concave gap between each of thesecond and third key caps and the rounded extension of the first keycap, whereby all three key caps fit closely together and provide forcursor control through the said shaft without interference with normaltyping operations.

Force sensing means such as force-sensitive resistors are coupled to theshaft for sensing forces applied to the shaft by the user for cursorcontrol. More specifically, the shaft is fixed to an actuator plate, andprotruding surfaces of the actuator plate are arranged to impart suchforces to the force-sensitive resistor areas. Various other force orpressure sensing means such as strain gauges may be used is similarmanner.

The foregoing and other objects, features and advantages of theinvention will become more readily apparent from the following detaileddescription of a preferred embodiment which proceeds with reference tothe drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a compound key according to the firstembodiment of the invention;

FIG. 2 is a front view of the compound key of FIG. 1;

FIG. 3 is a right side view of the compound key of FIG. 1;

FIG. 4 is a rear elevational view of the compound key of FIG. 1;

FIG. 5 is a top view of the compound key of FIG. 1 shown disposed in akeyboard, the surrounding keys being shown in phantom;

FIG. 6 is a bottom view of the compound key of FIG. 1.

FIG. 7 is a perspective view of the second embodiment of the compoundkey;

FIG. 8 is a front elevational view of the compound key of FIG. 7;

FIG. 9 is a left side view of the compound key of FIG. 7;

FIG. 10 is a right side view of the compound key of FIG. 7;

FIG. 11 is a rear elevation view of the compound key of FIG. 7;

FIG. 12 is a top view of the compound key of FIG. 7 shown disposed in acomputer keyboard, the surrounding keys being shown in phantom;

FIG. 13 is a bottom view of the compound key of FIG. 7.

FIG. 14 is a perspective view of a third embodiment of the compound key;

FIG. 15 is a front elevational view of the compound key of FIG. 14;

FIG. 16 is a left side view of the compound key of FIG. 14;

FIG. 17 is a right side view of the compound key of FIG. 14;

FIG. 18 is a rear elevation view of the compound key of FIG. 14;

FIG. 19 is a top view of the compound key of FIG. 14 shown disposed in acomputer keyboard, the surrounding keys being shown in phantom;

FIG. 20 is a bottom view of the compound key of FIG. 14.

FIG. 21 is a perspective view of the fourth embodiment of the compoundkey;

FIG. 22 is a rear elevational view of the compound key of FIG. 21;

FIG. 23 is a side view of the compound key of FIG. 21;

FIG. 24 is a front elevational view of the compound key of FIG. 21;

FIG. 25 is a top view of the compound key of FIG. 21 shown disposed in acomputer, the surrounding keys being shown in phantom;

FIG. 26 is a bottom view of the compound key of FIG. 21.

FIG. 27 is a perspective view of a pointing stick and keycap ensemble,according to the present invention;

FIG. 28 is a rear elevational view thereof;

FIG. 29 is a front elevational view thereof;

FIG. 30 is a right side, elevational view, the left side beingsubstantially a mirror image thereof;

FIG. 31 is a top plan view thereof.

FIG. 32 is a top view showing in dashed lines location of the forceactuator and force sensors.

FIG. 33 is cross-sectional view taken along line 10--10 of FIG. 32.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-6 illustrate a first embodiment of the invention. This is acompound key which has a pointing stick 110 that extends through anaperture 112 in one of the slanted sides 114 of the key cap. By a"pointing stick" we mean a button or stalk which is coupled to forcesensors, as further described below, for cursor control. Since thepointing stick extends slightly above the key cap, it can be actuatedand controlled by the user independently of the key cap which is usedfor typing. The beveled side wall 114 of the key cap has a roundedextension 116 in which the aperture 112 is formed. Aperture 112 is sizedto allow slight lateral motion of the pointing stick withoutinterference. The pointing stick may include an enlarged head or topportion 118 for better contact with the user's fingertip. The extension116 is limited in size so that it does not interfere with adjacent keycaps in a keyboard, as shown in FIG. 5. The head of the pointing stick,however, may extend slightly over adjacent key caps as shown withoutcontacting them. The internal components and operation of the compoundkey are described below with reference to the embodiment of FIGS. 27-33.

FIGS. 7-13 illustrate a second embodiment of the invention. This issimilar to the first embodiment, except that a pointing stick 210extends through an aperture 212 formed adjacent the comer of a key cap214. The key cap in this case is not extended beyond its usualdimensions. This ensures that the modified keycap 214 will fit withineven a very compact keyboard, such as in a laptop computer, withoutinterfering with adjacent keys. The internal components and operation ofthe compound key are described below with reference to the embodiment ofFIGS. 27-33.

FIGS. 14-20 illustrate a third embodiment of the invention. This issimilar to the second embodiment, except that pointing stick 310 isdisposed in an aperture 312, which is formed in an extension 314.Extension 314 is formed adjacent a corner, preferably a front corner, ofa key cap 316. In a keyboard, if required by keyswitch spacing, adjacentkeycaps can be modified to avoid interference with the compound key, asillustrated in FIG. 19. The internal components and operation of thecompound key are described below with reference to the embodiment ofFIGS. 27-33.

FIGS. 21-26 illustrate a fourth embodiment of the invention. This issimilar to the previous embodiments, except that here a pointing stick410 extends through an aperture 412 formed in a space bar key cap 414.This embodiment also has the advantage of providing a separate pointingstick like a joystick without using any additional keyboard space. Theinternal components and operation of the compound space bar key aredescribed below with reference to the embodiment of FIGS. 27-33.

FIGS. 27-33 illustrate a fifth embodiment of the invention. FIG. 27 is aperspective view of modified keycaps 388, 369, 370. One of the keycaps388 is modified to house a pointing stick, while the other key caps 369,370 are modified so as to fit closely around the pointing stick housingwithout contact. Key cap 388 includes a top surface 402 and dependingside walls, e.g. side wall 404, forming a perimeter of the key cap. FIG.28 is a front elevational view of the keycap combination, and FIG. 29 isa rear elevational view and FIG. 30 is a side elevational view. FIG. 31is a top view of the keycap combination and pointing stick asimplemented in a keyboard such as a computer keyboard, showingsurrounding keycaps of the keyboard in dashed lines.

FIG. 32 shows a top view of one embodiment of the keycap combination andpointing stick in greater detail as implemented in a keyboard. Referringto FIGS. 27-32, key cap 388 is specially adapted to house the pointingdevice. Keycap 388 includes a generally rounded extension 390 (FIG. 32)formed in the perimeter of the key cap. Extension 390 has a centralaperture 392 (see FIG. 33), sized to accommodate and clear (not touch) apointing stick shah 384 positioned therein. Extension 390 of keycap 388is generally flat on its top surface. The top surface of extension 390is generally lower than the top surface 402 of keycap 388. The keycapsoverlie a plastic substrate 288. Substrate 288 has an aperture formed init at each key location, as best seen in FIG. 33.

Keycaps 369 and 370 are modified in the comers adjacent keycap 388 so asto form a concave gap 394 between the keycaps and extension 390, as bestseen in FIG. 32. This arrangement has the advantage of providing apointing function in a keyboard without having to relocate anykeyswitches away from their usual, standard locations on the keyboard.Accordingly, typing may be done in the usual manner.

A pointing stick tip 386 is attached to shaft 384 and preferably has adiameter greater than aperture 392. Note in FIGS. 27-30 that the tipextends slightly above the top surfaces of the keycaps to provideconvenient access for manipulation of the pointing stick, for examplefor cursor control, without interfering with the adjacent keycaps.

FIG. 33 is a cross-sectional view of the keycap and pointing stickcombination described, taken along the inverted-V shape cross sectionline 10--10 of FIG. 32 as shown. Referring to FIG. 33, a keycap guide244 is shown located below the keycap 388. Sensing areas 248, preferablyare formed of force-sensitive resistors on a membrane 250. The shaft 384is fixed to a rigid actuator plate 246. Note that the shape of actuatorplate 246, as best seen in FIG. 32, fits between the keycap guides 244of surrounding keys. A pliable sheet, such as rubber, 266 is disposedbetween the actuator plate and the sensors. Actuator bumps 268 areformed in and protrude from the rubber sheet toward the sensors, fortransmitting forces from the shaft to the sensors.

Pointing stick tip 386 is shown on top of shaft 384, as noted above.There is a gap 400 between the bottom of tip 386 and the top surface ofrounded extension 390 on keycap 388. The hole 392 in extension 390provides for relative movement between the shaft 384 and keycap 388without contact between the shaft 384 and the keycap 388. This isnecessary for two reasons. The first reason is so the pressing of keycap388 does not affect the pointing stick. The second reason is to ensurethat all forces applied to tip 386 by user's finger reach the sensorslocated a locations 248. Any contact between the pointing stick and thekeycap would result in erroneous joystick sensor readings.

Shaft 384 may be joined to actuator plate 246 by any suitable means. Forillustration, a threaded connection is shown. A preload spring assembly181 acts between reference plate 174 and retainer assembly 176 to applya preloading force at all times. Applying a pre-load force to theforce-sensing resistor elements is important for the following masons.First, force-sensing resistor elements provide a high resistance when noforce is applied to the element. When even small initial force isapplied, on the order of a hundred grams, the sensing elements maysuddenly drop to an initial resistance on the order of a few hundredthousand ohms. This drastic change, or step response, is disconcertingto an operator and undesirable for most applications. The application ofa pre-load force to the sensing areas eliminates this initial stepresponse problem.

Connectors, such as rivets or screws, may be used to couple the retainer176 to the actuator plate 246. Preferably, posts 256 are integrallyformed in the retainer 176 and extend up through the intermediatemembers and through the actuator plate. The posts are secured byretainer rings as shown. Note that reference plate 174 and membrane 250have oversized apertures through which the posts extend, so that theposts do not contact these members even when the pointing stick is inuse.

During a pointing operation, for example to move a cursor, all forcesimparted to the pointing stick 386 by an operator are transmitted to theactuator plate 246 and, through the actuator surfaces, to theforce-sensing areas 248. As noted above, the force-sensing areas arepre-loaded to a predetermined operating point, so that a lateral forceapplied to the button 386 results in a differential electrical signalbecause the force applied to some of the force-sensing elements isincreased while the force applied to other force-sensing elements isdecreased. An arrangement of three sensors as shown, or four sensors,may be used. In the latter case, a force applied in any direction offthe X or Y axis results in resistance to change in all four sensingelements.

The pre-load spring 181 also affords the advantage of neutralizingmanufacturing variations in the various components described, as well asobviating a pivot's high tolerance requirements. In use, the compressedpre-load spring takes up variations in thickness of the elements inbetween the backup plate and the actuator plate to avoid any play orwobble in the assembly. As long as the force-sensing elements are biasedto some reasonable operating point, a processing unit coupled to theforce-sensing array can be arranged to calibrate itself to define zeroforce as whatever resistances are provided by the force-sensing elementsin the absence of externally applied forces.

Noteworthy is the absence of any pivot type supporting means as in aconventional joystick. Rather, the pointing stick is supported solely bythe actuator plate 246. Accordingly, downward or Z direction forces arecoupled through the actuator surfaces to the force sensing areas 248.The present apparatus thereby measures the overall or net force appliedby an operator. The net force can easily be computed by summing theforces on all the sensors. The net applied force information is usefulin many applications, for example, to control cursor speed, or toprovide Z axis control. Increasing the apparent cursor speed in responseto a greater operator applied force provides a natural and ergonomicallyefficient response.

Having illustrated and described the principles of my invention in apreferred embodiment thereof, it should be readily apparent to thoseskilled in the art that the invention can be modified in arrangement anddetail without departing from such principles. I claim all modificationscoming within the spirit and scope of the accompanying claims.

I claim:
 1. A compound key for use in a computer keyboard for bothtyping and cursor control, comprising:a key cap coupled to a keyswitchfor typing a predetermined alphanumeric character, the key cap having anaperture formed through it along a generally vertical direction forreceiving a shaft; a rigid shaft sized and arranged so as to extendthrough the aperture to a predetermined height slightly above a topsurface of the key cap for actuation by a user's fingertip; the aperturebeing sized so as to allow slight lateral motion of the shaft for cursorcontrol; and force sensing means coupled to the shaft for sensing forcesapplied to the shaft by the user for cursor control.
 2. A compound keyaccording to claim 1 wherein the key cap has a slanted beveled sidewall, and the aperture is formed in the side wall without enlarging thesize of the key cap.
 3. A compound key according to claim 1 wherein thekey cap is generally square and the aperture is formed adjacent a cornerof the key cap.
 4. A compound key according to claim 1 wherein the shaftincludes an enlarged head portion for receiving force applied by theuser's fingertip;the head portion arranged so as to extend slightly overthe top surfaces of adjacent key caps when the compound key is deployedwithin the typing array of keyswitches in a computer keyboard.
 5. Acompound key according to claim 1 wherein the key cap further includes an extension protruding therefrom, and the aperture for receiving theshaft is formed in the extension.
 6. A compound key according to claim 5wherein the extension is sized so as to clear adjacent key caps when theCompound key is deployed within the typing array of keyswitches in acomputer keyboard.
 7. A compound key according to claim 5 wherein theextension is located adjacent a front comer of the key cap.
 8. Acompound key according to claim 1 wherein the key cap is an elongatedspace bar key cap.
 9. An apparatus for use in a computer keyboardcomprising: a first key cap coupled to a first keyswitch for typing afirst alphanumeric character;a second key cap coupled to a secondkeyswitch for typing a second alphanumeric character; and a third keycap coupled to a third keyswitch for typing a third alphanumericcharacter; the first, second and third key caps being arranged adjacenteach other in a generally triangular configuration for fitting into atyping array of key caps in a computer keyboard; the first key capincluding a top surface and depending sidewalls, the sidewalls togetherforming a perimeter of the key cap, and further including an extensionformed in said perimeter of the key cap, the extension including acentral aperture formed therein for receiving a shaft; a rigid shaft,sized and arranged so as to extend through the aperture for actuation bya user's fingertip; the aperture being sized so as to allow slightlateral motion of the shaft for cursor control; force sensing meanscoupled to the shaft for sensing forces applied to the shaft by the userfor cursor control; and at least one of the second and third key capshaving a modified region so as to form a generally concave gap betweenthe said one key cap and the extension of the first key, whereby thesaid extension does not interfere with normal operation of the adjacentkey cap.
 10. An apparatus according to claim 9 wherein the extension isformed along a rear side wall of the first key cap; andat least one ofthe second and third key caps includes a respective modified portion soas to form a corresponding concave gap between said one key cap and theextension of the first key cap, whereby all three key caps fit closelytogether and provide for cursor control through the said shaft withoutinterference with normal typing operations.
 11. An apparatus accordingto claim 9 wherein the shaft extends generally upward through theaperture to a predetermined height slightly above the top surface of thefirst key cap so as to receive force applied by the user's fingertip forcursor control without actuating the first key switch.